The proposed goals of this research are: 1. To define the structural requirements for the selective inhibition of neuronal gaba uptake and gaba release by evaluating a series of systematically modified, easily accessible gaba derivatives, and to provide prototypical examples to serve as pharmacological diagnostics. 2. To develop selective electron microscopical visualizing agents for gaba-ergic nerve endings and glia based upon pharmacologically active gaba analogs containing in the structure an electron opaque atom (arsenic). 3. To resolve the questions of vesicular neuronal gaba storage by developing truly physiological methodology for demonstrations of vesicular uptake and release of gaba. The procedure would utilize the immobilization of vesicles on the inside wall of a poly-lysine coated tube, monitoring on a flow basis instantaneous 3H-gaba uptake, storage and release, and utilizing intracellular buffer and components (Mg ions/ ATP) possibly essential for the vesicular uptake of 3H-gaba. 4. To develop methodology for purification of gaba-ergic synaptosomes based upon affinity of the neuronal gaba system for gaba immobilized on the glycophase bonded to controlled pore glass beads.